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Jan. 2, 1962 J. w. JLJVINALL APPARATUS RoR AND METHOD oF CONVEYING ARTICLES 2 Sheets-Sheet 2 Original Filed May 22, 1952 INVENTOR.

JAMES W. JUVINALL BY SBM/W4,

A Harney United States Patent Oce Re. 25,108 Re'issued Jan. 2, 1962 25,108 APPARATUS FR AND METHOD F CNVEYING ARTICLES James W. .Iuvinall, Indianapolis, Ind., assignor to Ransburg Electro-Coating Corp., Indianapolis, Ind., a corporation of Indiana Original No. 2,769,728, dated Nov. 6, 1956, Ser. No. 239,333, May 22, 1952. Application for reissue July 1, 1958, Ser. No. 746,060

26 Claims. (Cl. 117--93) Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

This invention relates to apparatus for and method of conveying a series of articles along a predetermined path and is particularly directed toward varying the speed of or the spacing between the articles being so conveyed,

Article conveying apparatus has long been used in industry for transporting a series of articles in succession over a predetermined path. Continuously moving conveyors are commonly used for carrying articles of manufacture past a number of stations for the successive processing of the articles. One of the most common types of conveyors for this purpose comprises an I beam track positioned overthe desired path for the articles, a series of trolleys having rollers which ride on the upper surface of the lower flange of the I beam, article supporting structure joined to each trolley, and a power-driven flexible member as a cable or a chain. The trolleys are normally affixed, with a uniform spacing between them, to the power-driven flexible member' so that Athe trolleys, each carrying an article supporting structure, are moved in succession along the I beam track. In such conventional apparatus it is apparent that the speed and spacing as between adjacent articles are fixed'and may not be varied. f y

Itis often desirable that the articles be more intimately spaced as they [moved] move along a particular portion of the path or that the articles be moved past a predetermined point on the path at a speed which may be somewhat greater or less than the normal speed of the articles along the remainder of the path. A speed slower than normal may be desired for the articles as they move past a particular station to permit a certain operation on or to the article which requires Some time for its performance. Likewise, it may be necessary to"bunch up" the articles as they move past a station so as to present the articles at a conveniently close spacing for processing,

As one example of the flexibility in article spacing often sought in articleV conveying apparatus, the spray coating of relatively large rectangular articles, such as electric refrigerator cabinets, requires that the articles be normally spaced with a uniformly wide spacing between them to permit their being hung on the conveyor to permit certain pre-coating operations, or to allow the moving articles to turnv corners or move along an incline without danger of their bumping together. In a subsequent coating zone, however, close spacing is desired to prevent waste of coating material which would otherwise be projected between widely spaced articles and also to obtain a more uniform coating by presenting the closely spaced articles in an arrangement which approximates a continuous web or fiat sheet of material.

By positioning coating apparatus in the coating zone on eitherside of the moving articles two of the four sides of rectangular articles may be simultaneously coated but before the articles can be indexed or rotated 90 so that the other two sides of the articles may be presented for coating, itis necessary to first increase the spacing between the articles to permit indexing without bumping or contact between adjoining articles. Thus the spacing between the articles must be increased, the article then indexed and the spacing between the articles` again decreased to present closely spaced articles for ent-rance into the second coating zone where the two remaining sides of the article can be spray coated. As the articles leave the coating zone the spacing between articles should be increased to permit post-coating operations lto be performed on the articles and to remove the danger of contact between adjacent freshly coated surfaces.

An object of my invention is to provide an article conveying apparatus in which the speed of and/or spacing between articles may be vvaried as the articles move along the conveyor.

Another object of my invention is to provide means to minimize shocks on conveyor apparatus and to reduce interarticle motion when articles being conveyed undergo a change in velocity.

A further object is yto provide an improved apparatus and method for the spray coating of articles.

kStill another object is to provide an improved article supporting structure for supporting articles being carried on a moving conveyor.

A still further object is to provide for varying the speed of and/or spacing between articles carried on a conveyor and to do so in a positive and controlled manner.

Yet another object is to provide improved means to incrementally Kvary the speed or spacing of a series of article supports otherwise independently movable along a predetermined path.

My invention `provides for gradual, Le., .incremental acceleration or deceleration of conveyor-borne articles in a positive and controlledmanner over a substantial portion of their path of travel so as to prevent abrupt changes in the rate of movement of the article. In one embodiment of my'invention a part of each article `supporting structure may be disengaged from the main conveyoi track as the structure reaches a predetermined point where it is transferred to a separate track as an independently movable structure and propelled by a suitable pusher which moves at apositifvely controlled variable speed, thus to gradually accelerate or decelerate the movement of the article along specified portions of the path or to increase or decrease the spacing between articles as desired. When it is no longer required to vary the speed 'or' spacing of the articles, the structure may be transferred to and re-engaged with a conventional conveyor track for movement therealong at aconstant speed and with a xed distance vbetween the article supporting structures. Various other means for positively accelerating and/or decelerating a series of article supports along a predetermined path may be employed without departing from the scope ofrmy invention. For two applications which disclosure means for accomplishing this, reference is made to the co-pending application of Norman S. Curtis, Serial No. 291,723, dated June 4, 195,2, now Patent No. 2,752,883, andthe joint application of Norman S.k Curtis ber l0, 1952, now Patent NO. 2,751,851,

The principle of my invention may be utilized with especially benecial results in the coating of articles being moved on a series of independently movable article supports along a conveyor by proper coordination of apparatus for incrementally varying the velocity of the articles with spray coating apparatus.

Apparatus for accomplishing the above stated and related objects of my invention is hereinafter fully described with reference to the accompanying drawings wherein:

FIG. l is an elevational view, somewhat diagrammatic, of a preferred embodiment of my invention;

and Robert C. Juvinall, Serial No. 308,856, dated Septem- 3 y FIG. 2 is a cross sectional view of the apparatus shown in FIG. l, taken along line 2-2.

FIG. 3'is a detailed isometric View of a portion of the driving means shown in FIG. l;-

FIG. 4 is a diagrammatic elevation of apparatus ernbodying my invention and adapted for the spray coating of articles; and

FIG. 5 is an isometric view of the indexing and articlesupporting mechanism used in the apparatus shown in FIG. 4.

Referring first to FIGS. 1, 2 and 3, the articles to be coated (not shown) are suspended from a series of article supports 11, each of which extends downwardly from the lower face of an article-supporting horizontal square plate 12. A hook-engaging member 13 with a horizontal center section is connected to the upper face of plate 12. In those portions of the article path along which the articles are to travel in the conventional manner with uniform speed and spacing, the several article supporting structures (support 11, plate 12 and member 13) are carried and propelled by means of trolleys 14 which straddle the lower flange of the main I beam track 15, and which are provided with rollers 16 rolling along the upper faces of the lower flange of the I beam. Track is endless, in the manner of conventional trolley supporting conveyor tracks, so that the series of trolleys may pass repeatedly over it. Except over those portions of the article path in which movement of the articles is to be controlled in accordance with this invention, each of the article supporting structures is releasably connected to one of the trolleys as by a hook 17 pivotally connected to the trolley 14 by a transverse pin 18 and formed at its lower end to engage members 13 of the associated article supporting structure. Trolleys 14 are connected at spaced intervals in any convenient manner to an endless cable 19 which generally parallels the endless track 15 and is driven by a suitable source of power (not shown) at a uniform velocity. Along portions of the article path where the articles are to move at different speeds or spacings, the article supporting structures are disconnected from trolleys 14 in a manner now to be described.

As trolley 14 approaches that portionof the path along which a different speed or spacing of the articles is required, plate 12 moves over a separate conveyor track 20 which comprises two parallel series of vertical rollers 20a for supporting plate 12 and two series of horizontal rollers 20h arranged to lie on either side of theplate for guiding it along its predetermined path. At this point on the path, track 15 dips downwardly sufficiently so that plate 12 rests on track 20. At thev same time pusher 21 will come in contact with the rear edge of plate v12. Pusher 21 will be moving initially at a speed slightly in excess of the speed of trolley 14, and as track 15 continues to dip downwardly the lower portion of hook 17 will be entirely below and to the rear of the'horizontal center section of member 13. Plate 12 and member 13 will be propelled ahead of hook 17 and will be freed from the forward motion of cable 19. To insure the disengagement of hook 17 from member 13, cam 22 may be positioned over track 20, asby being suspended by suitable supports from the upper flange of I beam track 15. Cam 22 may be arranged cooperatively with lug 23 extending horizontally from hook 17 so that immediately after the hook has lowered plate 12 onto track 20, lug 23 will strike the leading edge of cam 22. The forward movement of trolley 14 will cause hook 17 to pivot about pin 18 so the lower end of the hook will move rearwardly and upward out of engagement position. Track 15 will then rise slightly thus raising hook 17 to. such a height that it can no longer engage a member 13 of any article supporting structure moving on track `20.

Plate 12 is then propelled along track 20 solely by means of pusher 21 by which the desired velocity changes are imparted to the varticle supporting structure. As shown pusher 21 is rigidly connected to and extends outwardly from a movable chain 24 which is mounted on driving sprocket 25 and idler sprocket 26 so that along its major portion chain 24 moves parallel to and above track 20. Sprocket 25 is mounted for rotation on suitable roller bearings about fixed shaft 27. Sprocket 25 is concentrically joined to sprocket 28 which is driven by a chain 29 from driving sprocket 30 which is keyed on shaft 31 extending from gear box 32. The speed of pusher 21 is controlled by the speed of rotation of sprockets 25 and 28 which is in turn controlled by the speed of rotation of sprocket 30 and shaft 31. Shaft 31 is driven by a step-up gear train within gear box 32.

Rotary power is supplied to gear box 32 by means of an eccentric pinion and elliptical gearing mechanism which is shown in detail in `FIG. 3. Shaft 33 is rotated at a constant speed from a convenient source of power (not shown). Pinions 34 and 35 are keyed to shaft 33. Smaller pinion 34 is concentric with the shaft and meshes with a half spur gear 36. Larger pinion 35 is eccentrically mounted on shaft 33 and meshes with a half elliptical gear 37; the two gear segments 36 and 37 being keyed to driven shaft 38 which is the input shaft of gearl box 32. The eccentric-elliptical combination of gearing may be be constructed to provide any desired velocity pattern within a wide range. In the embodiment shown one revolution of shaft 38 is obtained for every three revolutions of driving shaft 33; two revolutions of the concentric pinion 34 being required for a half revolution of shaft 38, and one revolution of eccentric pinion 35 for the remaining half revolution. This 360 cycle of rotary motion requiring one complete revolution of shaft 38 is imparted to the train of gears within gear box 32 where the cycle will be stepped up and translated to shaft 31. Thus while'pinion 34 is driving gear 36 there will be a relatively slow and uniform rotation of shaft 31 which may be approximately one-half of the speedof` trolleys 14, but as the eccentric pinion 35 starts to drive the speed of shaft 31 will be gradually accelerated and, after reaching a maximum which may be somewhat greater than the speed of trolleys 14, gradually deceleratedv toward the slow uniform speed. This cycle of motion may be properly coordinated and transmitted from shaft 31 through sprocket 30, chain 29, sprockets 25 and 28 and chain 24 to pusher 21, so as to provide the desired changes in velocity of pusher 21 for transmittal to the article supporting structure. The apparatus just described will impart a decelerating-const'ant velocity-accelerating cycle which will will decelerate during one quarterl of the cycle, remain constant during one half the cycle and accelerate during the remaining quarter of the cycle.

As shown pusher 21 rotates into propelling position and initially engages the rear edge of plate 12, which will be propelled yalong a small first portion of track 20 with an accelerating motion While power is being supplied from pinion 3-5 to the latter part of the speed accelerating portion of elliptical gear 37. This short period of acceleration will permit plate 12 to be pushed by pusher 21 at a rate slightly in excess of the ,speed of trolley 14 so that member 13 will move ahead of hook 17 and the hook may be disengaged from member 13 Vas previously described. Then, as power is supplied from the speed decelerating portion of elliptical gear 37,

the forward motion of plate 12 will be gradually decreased to permit successively trailing plates to catch up and to effect a decrease in the spacing between articles by a positive means and at a controlled gradual rate. Next, while pinion 34 drives spur gear 36, uniform motion will be transmitted to pusher 21 so that it will propel plate 12 at a constant slow speed and with a uniformly close spacing between articles.

While the articles are thus closely spaced they may be moved into cooperating position with appropriate processing equipment for lwhich close spacing of the articles is desired. After the articles have been processed while moving at a uniform close spacing, eccentric pinion 35 will again engage elliptical gear 37 so that the speed of pusher 211 will be incrementally increased along .a substantial portion of the path. Plate 12 will thus be incrementally accelerated toward the speed of cable 19. At this point on the path track 15 dips slightly downward so that hook 17 will be lowered into engaging position behind member 13. When pusher 21 carried on chain 2=4 reaches sprocket 26 the pusher will be revolved upwardly out of contact with plate 12, so that hook 17 will overtake the plate and again engage the horizontal center section of member 13. Track 15 here rises again and as trolley 14 moves upwardly it will lift plate 12 from. engagement with rollers 20a and article supporting structure will continue along track 15 at a constant velocity and with a uniform spacing between adjacent articles.

It is noted that pusher 21 undergoes two periods of acceleration-one at each end of its movement in engagement with plate 12and that the extent of such movement is somewhat less than one-half the developed length of chain 24. Accordingly it is possible,as shown, to mount two pushers 2.1 and 21' on chain 24, separating them by an interval equal to one-half the length of the chain, and to so proportion the chain-driving mechanism so that the chain traverses its entire length while shaft 38 is making two complete revolutions. The mechanism is so arranged that each pusher moves into and out of engagement with a plate 12 during a period of pusher acceleration and at times when the velocity of the pusher approximates that of cable 19. In the specific arrangement shown, each pusher is in engagement with a plate 12 for somewhat less than the interval required for a full cycle of motion transmitted by a 360 revolution of shaft 38 dueto the fact that during a one-half revolution of chain 24, a pusher must traverse the center-to-center `distance between sprockets and 26 plus one-half the circumference of either of these sprockets. Thus pusher volocity cannot exactly equal cable velocity both when the pusher engages with and disengages from the plate. Accordingly, at least at one of the instances when the article supporting structure changes from being cable-propelled to being pusherpropelled, or vice versa, it will undergo a somewhat abrupt change in velocity. This is not serious, ho-wever, for any such change can be small and, since it occurs when adjacent articles are at their maximum spacing, the slight inter-article movement which might result is not commercially objectionable.

As will be obvious the mechanism must include one pusher for each of the article supporting structures simultaneously traversing track 20 and all these pushers must be capable of independent movement to accommodate the changes in article spacing resulting from the desired acceleration and deceleration. In the device shown it is contemplated that four article supporting structures will move at any given time in seriatim along track 20 and accordingly three additional chains 24a, 24h, and 24e are provided. These chains, each of which mounts two pushers, are identical to chain 24, and are rotatably mounted on Idriving sprockets 25a, 25h and 25e respectively and on three separately rotatable idler sprockets (not shown but identical to idler sprocket 26). Driving sprockets 25a, 25h, and 25e are rotatably mounted concentrically with driving sprocket 252 on xed shafts 27 and 27a. As shown in FIG. 2, sprockets 25? and 25a are mounted on shaft 217 on one side of main track 15 with sprockets 25h and 2"5c mounted on fixed shaft 27a on the other side of track 15. Four separate power transmission systems each comprising a driven gear, a chain, a driving sprocket, a gear box and an eccentric-elliptical gear combination, identical to the power transmission system used for driving chain 24 as previously described,

are employed to independently drive sprockets 25a, 25h, and 25C respectively. The pushers mounted on chains 24, 24a, 24h and 24e are mutually spaced so as to accommodate a steady arrival of supporting plates 12 beneath the driving sprockets to be propelled in succession along track 20, and to deliver the article supporting structures in seriatim to the endl of track 20 appropriately timed for reengagement with a moving hook 17.

t FIGS. 4 and 5 show the above described embodiment of my invention adapted for the spray coating of the four sides of rectangularly shaped articles which maybe rectangular metal cabinets or the like. For convenience of illustration I have shown the articles 40 passing in succession through Zones A through I. Articles 40 are carried along main conveyor track 41 on a series of article supporting structures 42. In zone A the articles will move along track 41 at a constant rate and with uniform spacing between successive articles. As each successive article supporting structure 42 enters zone B a portion of supporting structure 42 and article 40 supported thereon is transferred from main track 42 to separate conveyor track 43. l

As articles 40 are transferred in succession from track 41 to 43 they will be propelled along a first portion of track 43 by a variable speed pusher mechanism 44 with a deceleration-constant velocity-acceleration speed cycle and this mechanism may be similar to the eccentric-elliptical gear driving means vshown in FIGS. l, 2 and 3. The articles move through zone B at an incrementally decelerating speed causing them to bunch up. Then the articles are moved at a constant slow speed through coating Zone C with Ia small spacing between successive articles. In zone C the articles move into cooperation with spray coating means which. may comprise three electrostatic lspray coating heads 45 positioned along track 43 on each of the two sides of the articles to be coated. Such an arrangement of spray heads is shown and vdescribed in my co-pending application, Serial No. 257,741, previously led on November 23, 1951, now Parent No. 2,839,425. The spray from each head 45 when positioned as set forth in my said co-pending application will blend with the spray from the two adjacent he'ads to form a uniform coating over the entire surface of each of the two outwardly facing sides of articles 40. l

As articles leave coating zone C and enter zone D the speed of the articles is incrementally increased throughout zone D sothat the spacing between successive articles will gradually increase to the speedof track 41. The articles then leave propelling means 44 and enter indexing zone E where the articles, still supported on track 43',

will be temporaritly re-engaged with the propelling means,

the articles will be successively indexed 90 las Iby the apparatus shown in FIG. 5 'and which will hereinafter be more fully described. The two remaining sides which were not spray coated as the articles passed through zone C will now be positioned outwardly so that these sides may be spray coated. The larticles then move into zone F for engagement with a second variable speed pusher mechanism 46 which may be generally similar to mecha-v nism 44. The articles in zone F are incrementally decelerated and then moved into coating zone G where the articles move at a constant slow speed past three electrostatic spraying heads 47 similar to those previously mentioned located on each side of articles 40 and arranged so that a uniform coating will be applied to the entire surface of each of the two outwardly facing sides of the article. Upon the articles leaving coating zone G they will be incrementallyaccelerated throughout the length of zone H by pusher mechanism 46. The acceleration of the articles in zone H must be especially gradual and without any appreciable inter-article movement due to lthe closely spaced, opposing freshly coated surfaces lof adjacent articles. Upon completion of this very gradual acceleration, the articles are returned to main conveyor track 41 for continued travel throughout zone I at a constant speed and with uniform wide spacing between articles.

FIG. shows the details of an indexing and article supporting mechanism adapted for embodiment in the apparatus shown in FIG. 4 and just described. Track 43 comprises two parallel supporting members 50 and 51 on which are mounted two parallel series of cylindrical idler rollers 52a and -52b which support horizont-al square plate 53 of the article supporting structure desig-v nated generally as 42. Plate 53 is guided b-y two parallel series of rollers 54a and 54h mounted on the horizontal flange of members 50 land 51 respectively. The use of such a horizontal hat plate will serve to substantially reduce swinging, swaying and other inter-article movement Abecause of the stability and suppo-rt furnished to the article supporting structure lby the wide horizontal expanse of the plate. This improved article stability is important not only to substantially eliminate inter-article contact, but also to prevent appreciable movement or swaying of' articles transverse to the conveyor path which in a coating zone will cause fluctuations in the spacing between the spray source, as for example head 47, and the articles which in turn might well result in objectionable variations inthe pattern of the spray.

Bracket 55 is connected to the bottom face of plate 53 and this bracket supports article hanger 56. Upper segment 57a of positioning cam 57 is rigidly affixed to the upper end of hanger 56 and ilower segment 57h of this cam is mounted on bracket 55. A four-toothed cam wheel 58 is rigidly mounted concentrically about hanger 56. As plate 53 is propelled through zone E along track 43 one of the teeth of cam wheel SS will strike indexing arm 59, arm 59 being positioned along track 43 as shown in FIG. 4 thus causing article hanger 56 and supported article 49 to rotate 90. After vbeing indexed the article wil-l be held in its new position by positioning cam 57.

While I have disclosed specific apparatus, Iby Way of example, to illustrate my invention, numerous modifications and adaptations may be made without departing from the scope of my invention. It is to be understood that my invention is not limited to the apparatus herein described Ebut that the scope of the invention is that set forth in the appended claims.

I claim:

1. A method of coatingl the sides of a plurality of generally cubically shaped articles as the articles move along a predetermined path comprising supporting the 4articles in seriatim along a track with adjacent outwardly facing sidesof adjacent articles positioned in common planes, said outwardly facing sides of said adjacent articles forming two substantially continuous surfaces to be coated, moving said articles through a first `coating zone, spray coating the outwardly facing opposite sides of said articles, uniformly increasing the spacing bet-ween adjacent articles, indexing each article approximately 90, uniformly decreasing the `spacing between articles until adjacent outwardly facing sides of the articles form two substantially continuous surfaces to be coated, moving said articles through a second coating zone, and spray coating the outwardly facing opposite sides of said articles.

2. An article coating apparatus comprising a series of independently movable supports for the articles to be coated, means for guiding said supports in succession over a predetermined path, means for moving said supports along a rst portion of said path at a constant rate and with a uniformly wide spacing between supports, means for moving said supports with a gradually decreasing spacing between said supports along a second portion of said path, means for moving said supports along a third portion of said path at a constant rate and with a uniformly close spacing between supports,

spray coating means` located along said third portion of said path and in coating cooperation with respect to the articles carried by said'supports traversing said third portion of the path, means for moving said supports with a gradually increasing spacing between said supports along a fourth portion of said path, means for moving said supports at such increased spacing along a fifth portion of said path, indexing means for rotating each support through an arc of at a predetermined point along said fifth portion of the path, means for moving said supports with a gradually decreasing spacing between said supports along a sixth portion of said path, means for moving said supports along a seventh portion of said path at a constant rate and with uniformly .close spacing between supports, spray coating means located 'along said seventh portion of said path and in coating cooperation with respect to the articles carried by said supports traversing said seventh portion of the path, means for moving said supports with a gradually increasing spacing between said supports along an eighth portion of said path, 'and means for moving said supports along a ninth portion of said path at a constant rate and Kwith a uniformly wide spacing between supports.

3. An article conveying apparatus comprising a series of independently movable article supports each including a horizontal plate; first and third guiding means for guiding said supports in succession over rst and third portions of a predetermined path; first propelling means for propelling said supports over the first and third portions of said path at a constant rate and with uniform spacing between said supports; second guiding means comprising a series of idler supporting rollers supporting said horizontal plate and also a series of idler guiding rollers on either side of said plate and extending in the direction of said predetermined path for guiding said supports in succession over a second portion of said path; means for disengaging said first propelling means from said supports as the supports enter said second guiding means; second propelling means for propel-ling said supports along said second guiding means at a controlled variable speed; means at the end of said second guiding means for disengaging said second propelling means from said supports and means for re-engaging said first propelling means with said supports to propel said supports along said third pontion of said path.

4. A conveying `apparatus for conveying a series of articles along a predetermined path comprising a main conveyor track; an auxiliary conveyor' track; a series of trolleys movably mounted on said main conveyor track; means for moving said trolleys with uniform speed and spacing Aalong said main conveyor track; a series of articie supports carried alo-ng a portion of said main conveyor track by said trolleys each comprising a horizontal plate, an article hanger rigidly depending from said plate, and a member connecting said support to said trolley; means operative on said connecting means positioned along said auxiliary conveyor track for disconnecting said article supports from said trolleys; land means for propeiling said article supports along a portion of said auxiliary conveyor track at an incrementally varying rate.

5. An article coating apparatus comprising a series of independently movable supports for the articles to be coated, means for guiding said supports in succession over a predetermined path, means for moving s-aid supports along a first portion of said path at a constant rate and with relatively wide spacing between adjacent supports, means for moving said supports` over a second portion of said path at a rate gradually reducing from the rate of movement of said supports along said first path portion to a substantially lower rate and with a gradual reduction in spacing between adjacent supports traversing said second path portion and then moving said supports over a third portion of said path at said lower rate and with a relatively close spacing between supports, and spray coa-ting means located along said third portion of said path and in coating cooperation with respect to the articles arriba carried by said supports traversing said third portion of the path for spray coating the articles.

6. An overhead conveying system for conveying an article along a predetermined generally horizontal path on a support while retaining the article in a fixed position relative to said support comprising a horizontal 4plate having a substantial extent both parallel to and traverse of the article path, an article support rigidly depending from said plate, means for rigidly mounting the article to be conveyed on said support, va conveyor track extending along said predetermined path, a series of plate-supporting rollers mounted on said conveyor track and extending along said predetermined path, two series of plate-guiding members mounted on said conveyortrack and extending along opposite sides of said path, and means for moving said horizontal plate over said plate-supporting rollers and between said plate-guiding members. v

7. A conveying apparatus for conveying a series of articles along a predetermined generally horizontal path comprising a main conveyor track; an auxiliary conveyor track; a series of trolleys movably mounted on said main conveyor track; means for moving said trolleys with uniform speed and spacing along said conveyor track; a series of article supports carried along a portion of said main conveyor trac-k by said trolley each comprising a horizontal plate having a substantial extent parallel to the article path, an article hanger rigidly depending from said plate, and a member connecting said support to said trolley; means for successively disconnecting said article supports from saidtrolleys at a point adjacent the initial portion of said auxiliary conveyor track; said auxiliary track being positioned to supportingly engage the plate of each article support after such support is disconnected from a trolley; rneans for propelling said article supports on said plates in seriatim along said auxiliary conveyor track; and means for re-connecting said article supports to said trolleys at a point adjacent the final portion of said auX- iliary conveyor track.

8. A method of processing a plurality of articles, cornprising moving the articles in succession along a predetermined path, maintaining each article at a substantially constant velocity until it reaches a predetermined point in such path, then gradually decelerating each article as it proceeds along a substantial portion of said path until it attains a predetermined relatively low velocity thereby reducing the spacing between it and the following article, moving the articles with reduced spacing and at low velocity along said path through a processing zone, and then, as each article reaches a second predetermined point along said path, gradually accelerating the article along. arsubstantial portion of said path to increase the distance between it and the fol-lowing article.

9. An article conveying apparatus comprising a series of article supports, means for guiding said supports in succession over a predetermined path, first propelling means for propelling a plurality of said supports simultaneously over a first portion of said path at `a constant rate and with a uniformly wide spacing between adjacent supports, second propelling means for propelling a plurality of said supports simultaneously over a second portion of said path at a rate gradually reducing from the rate of movement of said first propelling means to a substantially lower rate and with a gradual reduction in the spacing 'between adjacent supports traversing said second portion of the path, means for disengaging said first propelling means from each lone of said supports as each support enters said second portion of said path, and means for engaging said second propelling means with each support substantially simultaneously witih the disengagement therefrom of said first propelling means to effect a smooth gradual reduction in the spacing between adjacent articles on said conveying apparatus.

10. An article conveying apparatus comprising a series of article supports, means for guiding said supports in succession over a predetermined path, irst propelling means 10 for propelling a plurality of said supports simultaneously over a first portion and also a fourth portion of said path at a constant rate and with a uniformly wide spacing between adjacent supports, second propelling means for propelling a plurality of said supports rst over a second portion of said path at a rate gradually reducing from the rate of movement of said rst propelling means to a substantially lower rate and then over a third portion of said path at a rate gradually increasing from said lower rate to substantially the rate of movement of said first propelling means, means for disengaging said first propelling means from each one of said supports as each support enters said second portion of said path, means for engaging said second propelling means with each support substantially simultaneously with the disengagement therefrom` of said first propelling means, means for disengaging said second propelling means from each one of said supports as each support enters the fourth portion of said path, and means for re-engaging said first propelling means with each support substantially simultaneously with the disengagement therefrom vof said second propelling means.

ll. An article conveying apparatus comprising a series oiarticle supports, a first `conveyor track for guiding said supports in succession over a lirst predetermined path portion, first propelling means for propelling a plurality of said supports simultaneously over said first path portion at a constant rate and with a uniformly wide spacing between adjacent supports, a second conveyor track for guiding said supports in succession over a second predetermined path portion, second propelling means for propelling a plurality of said supports simultaneously over said second path portion at a rate gradually reducing from the rate of movement of said first propelling means toa substantially lower rate and with a gradual reduction in the spacing between adjacent supports .traversing said second path portion, Imeans operative individually on each one of said supports as each support reaches the end of said rst path portion for transferring said support from said -rst conveyor track to said second conveyor track and for disengaging said first propelling means from said support, and means for engaging said second propelling means with each support substantially simultaneously with the disengagement therefrom of said rst propelling rneans to eiect a smooth transfer of articles from one conveyor track to the other and a gradual reduction in the spacing between adjacent articles on said conveying apparatus.

12. Work handling apparatus for spray painting and the like comprising ai first conveyor having propelling means movable along a predetermined path of travel, coupling means carried by said first conveyor at spaced points allang the length thereof and extending therefrom, work holders having engagement meansvrespecl'vely engageable with and dsengageable from said coupling means lo enable the work holders to be carried by the coupling means, a seco/rd conveyor having propelling means movable along a path of travel which extends in the same generail direction as the path of travel of the first conveyor, antifricton means forming a part of said second conveyor and forming an engagement track along a length thereof, guide means for moving the propelling means of the first conveyor and the engagement track of' the second conveyor relatively toward and away from each other to enable the engagement and disengagement of said work holders with said track, and means for driving the propelling means of said conveyors at relatively different speeds whereby to control the manne-r of interaction between the coupling means and the engagement means of the work holders.

13. Work handling apparatus as defined in claim 12, wherein the first conveyor is disposed above the Second conveyor, and the work holders are deposited upon the antfricton means of the second conveyor by gravity.

14. Work handling apparatus as defined n claim 12 11 wherein the means for driving the second conveyor propeiling means is cyclically operable at variable speeds.

75. Work handling apparatus for spray painting and the like comprising a hrst conveyor having propelling means movable along a predetermined path of travel, coupling means carried by said first conveyor at spaced points along the length thereof and extending therefrom', work holders having engagement means respectively engageable with and disengageable from said couptling means to enable the work holders to be carried by the coupling means, a second conveyor having propelling means movable along a path of travel which extends in the same general direction as the path of travel of the first conveyor, antifriction means forming a part of said second conveyor and forming an engagement track along a ilength thereof, guide means for moving the propelling means of the first conveyor and the engagement track of the second conveyor relative-ly toward and away from each other to enable the engagement and disengagement of said work holders with said track, means for driving the propelling means of said conveyors at relatively different speeds, and cam means engageable with the coupling means, the manner of interaction between the coupling means ana' the engagement means of the work holders being controlled by the cam means and the relatively different speeds of the conveyor propelling means.

16. Work handling apparatus comprising a first conveyor movable along a predetermined path of travel, hooks depending from the conveyor at points spaced from each other lengthwise of the conveyor and facing the direction of advancement of the conveyor, means respectively pivotally mounting the upper ends of the hooks on the conveyor for swinging movement about axes extending transversely of the path of travel of the conveyor, work holders having parts respectively engageable by the hooks, a second conveyor supported below the first conveyor having means arranged for movement along a path of travel which extends in the same general direction as the path of travel of the first conveyor and having supporting rollers, a guide for the rst conveyor and having means for directing the rst conveyor downwardly toward the second conveyor to deposit the work holders on the rollers of the second conveyor and to lower the hooks relative to the work holders, means for driving said Orst conveyor and for driving the second conveyor moving means at a rate slower than the Jrst conveyor to reduce the spacing between adjacent work holders on the second conveyor and to swing said hooks rearwardly about their pivots, and means for controlling the rate of deceleration of the work holders as they are deposited on the second conveyor.

17. Work handling apparatus comprising a first conveyor movable along a predetermined path of travel, hooks depending from the conveyor at points spaced from each other lengthwise of the conveyorand facing the direction of advancement of the conveyor, means respectively pivotally mounting the-upper ends of the hooks on the conveyor for swinging movement about axes extending transversely of the path of travel of the conveyor, work holders having parts respectively engageable by the hooks, a second conveyor supported below the first conveyor having means arranged for movement along a pathv of travel which extends in the same general direction as the path of travel of the first conveyor and having antifriction means for supporting said work holders, guide means for relatively moving said conveyors toward each other to deposit said work holders on the anti-friction means of said second conveyor and to lower said hooks relative to said work holders, means for drivingsaid first conveyor and for driving the moving means of said second conveyor at a rate of speed slower than said rst conveyor to reduce the spacing between adjacent work holders on the anti-friction means of said second conveyor and to swing said hooks rearwardly about their pivots, and means for controlling the rate of deceleration of said work holders as they are deposited on the antifriction means of said second conveyor.

18. The work handling apparatus defined in claim` 17 comprising means responsive to continued advancement of said hooks by said first conveyor beyond said controlling means for swinging said hooks further in a. rearward direction completely out of engagement with said parts of said holders to thereby release said holders from said first conveyor.

19. Work handling apparatus comprising hrst and second conveyors supported one above the other and having means arranged for movement in the same general direction, work holding means movable through the space between said conveyors,means releasably coupling said work holding means to the upper conveyor, means responsive to advancement of said work holding means by said upper conveyor for depositing said work holding means on the lower conveyor, means for driving said zipper conveyor moving means and for driving said lower conveyor moving means at a rate of speed slower than that of said upper conveyor moving means, means cooperable with said coupling means for controlling the rate of deceleration of said work holding means from the speed of said upper conveyor moving means to the speed of said lower conveyor moving means following initial deposit of said work holding means on said lower conveyor, and means for disconnecting said coupling means from said work holding means after the aforesaid deceleration of said work holding means.

20. Work handling apparatus comprising an upper conveyor movable along a predetermined path of travel, coupling means depending from said upper conveyor at points spaced lengthwise thereof, work holders having parts respectively engageable with said coupling means, a lower conveyor supported below said upper conveyor having means arranged for movement along a path of travel which extends in the same general direction as the path of travel of said upper conveyor, anti-friction means on the top surface of said lower conveyor, guide means for relatively moving said conveyors toward each other to deposit said work holders on the anti-friction means of said lower conveyor, means responsive to continued advancement of said coupling means after the deposit of said work holders on the anti-friction means of said lower conveyor for moving said coupling means to a position out of engagement with said work holders to release the latter', means responsive to continued advancement of said coupling means beyond the point of release to return said coupling means to a position engageable with said work holders, means for driving said upper conveyor and for driving said lower conveyor moving means at a rate of speed slower than said upper conveyor enabling said coupling means to overtake the work holders n advance thereof and to engage said work holders and advance the same at the speed of said upper conveyor wh'ile supported by said lower conveyor, ami guide means located a predetermined distance beyond tlze point of.

engagement of said coupling means with said work holders for relatively moving said conveyors apart to transfer said work holders from the lower to the upper conveyor.

21. Work handling apparatus comprising an upper conveyor movable along a predetermined path of travel, hooks pivoted to and depending from said conveyor at points spaced lengthwise thereof and facing in the direction of advancement of said conveyor, work holders having parts respectively engageable with said hooks, a lower conveyor supported below said upper conveyor having means arranged for movement along a path of travel which extends in the same general direction as the path of travel of said upper conveyor, anti-friction means on the top surface of said lower conveyor, guide means for relathe anti-friction meansof said lower conveyor for swinging said hooks out of engagement with said parts to release the latter, means responsive to continued advancement of said hooks beyond the point of release to swing said hooks to a position engageable with said hook-engaging parts, variable drive means for driving said upper conveyor and for driving the moving means of said lower" conveyor at a rate of speed slower than said upper conveyor enabling said hooks to overtake the work holders in advance thereof and engage the hook-engaging parts of said work holders and advance the same at the speed of said upper conveyor while supported by said lower conveyor, and guide means located a predetermined distance beyond the point of engagement of said hooks and hookengagng parts for relatively moving said conveyors apart to transfer said work holders from the lower to the.' upper conveyor.

22. The work handling apparatus defined in claim 21 in which said anti-friction means comprises rollers journalled on said lower conveyor 'with their axes extending transversely thereof.

23. Work handling apparatus comprising a lower conveyor having means movable along a predetermined path of travel, work holders supported on said lower conveyor in spaced relation lengthwise thereof, means ,for removing said work holders from said lower conveyor comprising an upper conveyor spaced above said lower conveyor for movement along a path of travel which extends in the same general direction as the path of travel of said lower conveyor moving means and having coupling means depending from said upper conveyor atV of engagement of said coupling means with said work holders for relatively moving said conveyors apart to complete the transfer of said work holders from the lower to the upper conveyor, said lower conveyor having anti-friction means on the top surface for supporting said work holders.

24. Work handling apparatus comprising a lower conveyor having means movable along a predetermined path of travel, work holders supported on said lower conveyor in spaced relation lengthwise thereof and having hookengaging parts, means for removing said work holders from said lower conveyor comprising an upper conveyor spaced above said lower conveyor for movement along a path of travel which extends in the same general direction as the path of travel of said lower conveyor moving means and having hooks depending from said upper conveyor at points spaced from each other lengthwise thereof, means responsive to advancement of said upper conveyor for successively lowering said hooks to positions engageable with said hook-engaging parts, means for driving said upper conveyor and for driving said lower conveyor moving means at a rate of speed slower than said upper conveyor enabling saidhooks to overtake the work holders in advance thereof andr engage the hook-engaging parts of said work holders and advance the same at the speed of said upper conveyor while supported by said lower conveyor, and guide means located a predetermined distance beyond the point of engagement of said hooks and hook-engaging parts for relatively moving-said conveyors apart to complete the transfer of said work holders from the lower to the upper conveyor.

25. The work handlingapparatus defined in claim Y24 in which said anti-friction means comprise rollers journalled on said lower conveyor with their axes extending transversely thereof.

26. Work handling apparatus comprising a first conveyor movable along a predetermined path of travel,

hooks depending from the conveyor at points spaced from each other lengthwise of the conveyor ana' facing the direction of advancement of the conveyor, means respectively pivotally mounting the upper ends of the hooks on the conveyor for swinging movement about axes extending transversely of the path of travel of the conveyor, work holders having parts respectively engageable by the hooks, a second conveyor supported below the yrst conveyor having means arranged for movement along a path of travel which extends in the same general direction as the path of travel of the first conveyor, guide means for relatively moving said conveyors toward each other to deposit said work holders o-n said second conveyor and to lower said hooks relative to said work holders, means for driving said first conveyor and for driving said second conveyor moving means at a rate of speed slower than said first conveyor to reduce the spacing between adjacent work holders on said second conveyor and to swing said hooks rearwardly about their pivots as said work holders are deposited o-n said second conveyor, means cooperable with said hooks for controlling the rate of deceleration of said work holders from the speed of said rst conveyor to the speed of the moving means of said second conveyor following initial deposit of said work holders on said second conveyor, and means responsive to continued advance of said hooks by said first conveyor beyond said controlling means for swinging said hooks further in a rearward direction about their pivots completely out of engagement with said parts of said holders to thereby release said holders from said jrst conveyor.

References Cited in the le of this patent or the original patent UNITED STATES PATENTS 

